Do you know if this is true even taking into consideration that most people who pay for a Dexcom out of pocket stretch supplies? For example, if I were to use the Dexcom exactly as it is approved, I would be spending about $6,700 a year. But I stretch the transmitter, receiver, and sensors until they each die, which has decreased my cost to about $2,300 a year.
The Libre was just approved in Canada. My understanding is that, even though it's cheaper than using a Dexcom without stretching supplies, it would still be significantly more expensive for me to switch over. So I would be paying more than I am with fewer features (namely no alarms, which I find invaluable). I'll be very curious to see what insurance companies and governments do with the Libre, since it's not a CGM and can apparently replace fingersticks entirely. If I could get the Libre fully or almost fully covered, that would be worth switching.
As to the topic of the original post, my target range is 4.0 - 8.0 and for the past 30 days I've had 60% of readings in range, 33% high, and 7% low. I would find it very challenging to achieve this level of control without the alarms the Dexcom provides (I have my alerts set to 4.5 - 7.5 to give me 0.5 mmol/L warning to take action before I exit my target range), eating low-carb, using a pump, and using Fiasp insulin. If you are feeling comfortable with your level of control, it's never a bad thing to try to aim for tighter control. Just go slowly and don't burn yourself out trying.